leetcode 1457. Pseudo-Palindromic Paths in a Binary Tree 二叉树中的伪回文路径

Problem: 1457. Pseudo-Palindromic Paths in a Binary Tree 二叉树中的伪回文路径回溯深度优先搜索哈希表统计每个数字的频次当是叶子节点时统计频次中奇数的个数只有频数的奇数个数1才是伪回文串Codeclass Solution { public: vectorint ump; int count 0; void dfs(TreeNode* root) { if(rootnullptr) return; ump[root-val]; if(root-leftnullptr root-rightnullptr) { bool find true; int cnt 0; for(int i 1; i 10; i) { if(ump[i] 0) { if( (ump[i]1)1 ) cnt; if(cnt 1) { find false; break; } } } if(find) count; } dfs(root-left); dfs(root-right); ump[root-val]--; } int pseudoPalindromicPaths (TreeNode* root) { ump.assign(10, 0); dfs(root); return count; } };